On 2017-05-15 15:25:01 +0200, Mason wrote: > Isn't it UB to (re)define standard functions? Hmm... Actually yes, if there is an external linkage (7.1.3). So, I would expect a warning by the compiler, as this should be easily detectable. For fma(), this is also an incompatibility introduced by C99 (AFAIK, fma wasn't reserved in C89). -- Vincent Lefèvre <vincent@xxxxxxxxxx> - Web: <https://www.vinc17.net/> 100% accessible validated (X)HTML - Blog: <https://www.vinc17.net/blog/> Work: CR INRIA - computer arithmetic / AriC project (LIP, ENS-Lyon)